Olfactory Orientation and Navigation in Humans.

Lucia F Jacobs,Jennifer Arter,Frank J Sulloway,Amy Cook,Matthieu Louis

doi:10.1371/journal.pone.0129387

Lucia F Jacobs, Jennifer Arter + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0129387

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Journal: PloS one	Publication Date: Jun 17, 2015
Citations: 97	License type: CC BY 4.0

Affiliation: University of California, Berkeley

Abstract

Although predicted by theory, there is no direct evidence that an animal can define an arbitrary location in space as a coordinate location on an odor grid. Here we show that humans can do so. Using a spatial match-to-sample procedure, humans were led to a random location within a room diffused with two odors. After brief sampling and spatial disorientation, they had to return to this location. Over three conditions, participants had access to different sensory stimuli: olfactory only, visual only, and a final control condition with no olfactory, visual, or auditory stimuli. Humans located the target with higher accuracy in the olfaction-only condition than in the control condition and showed higher accuracy than chance. Thus a mechanism long proposed for the homing pigeon, the ability to define a location on a map constructed from chemical stimuli, may also be a navigational mechanism used by humans.

Highlights

There are two very different ways to use odors to orient in space
To ascertain that participants were disoriented before and after sampling the target location, we analyzed their ability to point to the start location three times
Participants were more confident in their estimates in the Olfaction condition than in the Control condition, indicating that they had a conscious awareness of their ability to navigate using odors

Summary

Introduction

The first is odor tracking, where an animal tracks an odor to its source. This behavior has been demonstrated in walking, flying and swimming invertebrate species [1,2,3] as well as walking, flying and swimming vertebrates [4,5,6]. Even blindfolded humans can crawl and track an odor across grass, and their accuracy in tracking decreases if they are deprived of bilateral nostril input [7]. Orienting more accurately with stereo-olfaction is evidence that an animal is using odors to compute the direction to the source [8,9,10]. Blindfolded humans can localize an odor’s source by sampling from a central, sitting location [11]

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